From: Borislav Petkov <bp@alien8.de>
To: Thomas Garnier <thgarnie@chromium.org>
Cc: kernel-hardening@lists.openwall.com, kristen@linux.intel.com,
keescook@chromium.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Juergen Gross <jgross@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Maran Wilson <maran.wilson@oracle.com>,
Feng Tang <feng.tang@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 08/11] x86/boot/64: Adapt assembly for PIE support
Date: Fri, 9 Aug 2019 19:30:03 +0200 [thread overview]
Message-ID: <20190809173003.GG2152@zn.tnic> (raw)
In-Reply-To: <20190730191303.206365-9-thgarnie@chromium.org>
chOn Tue, Jul 30, 2019 at 12:12:52PM -0700, Thomas Garnier wrote:
> Change the assembly code to use only relative references of symbols for the
> kernel to be PIE compatible.
>
> Early at boot, the kernel is mapped at a temporary address while preparing
> the page table. To know the changes needed for the page table with KASLR,
These manipulations need to be done regardless of whether KASLR is
enabled or not. You're basically accomodating them to PIE.
> the boot code calculate the difference between the expected address of the
calculates
> kernel and the one chosen by KASLR. It does not work with PIE because all
> symbols in code are relatives. Instead of getting the future relocated
> virtual address, you will get the current temporary mapping.
Please avoid "you", "we" etc personal pronouns in commit messages.
> Instructions were changed to have absolute 64-bit references.
From Documentation/process/submitting-patches.rst:
"Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
to do frotz", as if you are giving orders to the codebase to change
its behaviour."
Thx.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-08-09 17:29 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 19:12 [PATCH v9 00/11] x86: PIE support to extend KASLR randomization Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 01/11] x86/crypto: Adapt assembly for PIE support Thomas Garnier
2019-08-05 16:32 ` Borislav Petkov
2019-08-05 16:54 ` Kees Cook
2019-08-05 17:27 ` Borislav Petkov
2019-08-05 17:53 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 02/11] x86: Add macro to get symbol address " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 03/11] x86: relocate_kernel - Adapt assembly " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 04/11] x86/entry/64: " Thomas Garnier
2019-08-05 17:28 ` Borislav Petkov
2019-08-05 17:50 ` Thomas Garnier
2019-08-06 5:08 ` Borislav Petkov
2019-08-06 8:30 ` Peter Zijlstra
2019-08-06 12:35 ` Borislav Petkov
2019-08-06 13:59 ` Steven Rostedt
2019-08-06 15:35 ` Borislav Petkov
2019-07-30 19:12 ` [PATCH v9 05/11] x86: pm-trace - " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 06/11] x86/CPU: " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 07/11] x86/acpi: " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 08/11] x86/boot/64: " Thomas Garnier
2019-08-09 17:30 ` Borislav Petkov [this message]
2019-10-29 21:29 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 09/11] x86/power/64: " Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 10/11] x86/paravirt: " Thomas Garnier
2019-07-31 12:53 ` Peter Zijlstra
2019-08-12 12:55 ` Borislav Petkov
2019-10-29 21:30 ` Thomas Garnier
2019-07-30 19:12 ` [PATCH v9 11/11] x86/alternatives: " Thomas Garnier
2019-08-12 13:57 ` Borislav Petkov
2019-10-29 21:31 ` Thomas Garnier
2019-08-06 15:43 ` [PATCH v9 00/11] x86: PIE support to extend KASLR randomization Borislav Petkov
2019-08-06 15:50 ` Peter Zijlstra
2019-08-29 19:55 ` Thomas Garnier
2019-09-06 23:22 ` Thomas Garnier
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